Swapping Nodes in a Linked List - LeetCode 1721

 You are given the head of a linked list, and an integer k.

Return the head of the linked list after swapping the values of the kth node from the beginning and the kth node from the end (the list is 1-indexed).

 

Example 1:

Input: head = [1,2,3,4,5], k = 2
Output: [1,4,3,2,5]

Example 2:

Input: head = [7,9,6,6,7,8,3,0,9,5], k = 5
Output: [7,9,6,6,8,7,3,0,9,5]

Example 3:

Input: head = [1], k = 1
Output: [1]

Example 4:

Input: head = [1,2], k = 1
Output: [2,1]

Example 5:

Input: head = [1,2,3], k = 2
Output: [1,2,3]

 

Solutions(Only function):

class Solution {

    public ListNode swapNodes(ListNode head, int k) {

        

        ListNode first=head;

        

        k=k-1;

      

        while(k>0)

        {

            first=first.next;

            k--;

        }

        ListNode f=first;

        ListNode second=head;

      

        while(first.next!=null)

        {

            first=first.next;

            second=second.next;

        }

        int temp=f.val;

        f.val=second.val;

        second.val=temp;

        return head;

    }

}